Data Structures & Algorithms — C++ & Python

A structured day-by-day DSA problem plan for developers who prefer a logic-first approach.

🔹 Same problem handled in C++ and Python
🔹 Focus on algorithms & problem-solving, not copy-paste code
🔹 Designed for future full-stack & AI developers

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60 Day plan

Day	Topic	Problem / Question	Algorithm	Notes	C++	Python
01	Basics	Find Maximum Element in Array	Algo/day-01.md	Notes/Array.md	cpp/day-01.cpp	python/day-01.py
02	Arrays	Analyze Time & Space Complexity	Algo/day-02.md	Notes/Array.md	cpp/day-02.cpp	python/day-02.py
03	Arrays	Linear Search	Algo/day-03.md	Notes/Searching.md	cpp/day-03.cpp	python/day-03.py
04	Arrays	Reverse an Array	Algo/day-04.md	Notes/Array.md	cpp/day-04.cpp	python/day-04.py
05	Arrays	Find Second Largest Element	Algo/day-05.md	Notes/Array.md	cpp/day-05.cpp	python/day-05.py
06	Arrays	Remove Duplicates from Sorted Array	Algo/day-06.md	Notes/Array.md	cpp/day-06.cpp	python/day-06.py
07	Arrays	Rotate Array by K Positions	Algo/day-07.md	Notes/Array.md	cpp/day-07.cpp	python/day-07.py
08	Two Pointers	Pair with Given Sum (Sorted)	Algo/day-08.md	Notes/Two-Pointers.md	cpp/day-08.cpp	python/day-08.py
09	Two Pointers	Move All Zeros to End	Algo/day-09.md	Notes/Two-Pointers.md	cpp/day-09.cpp	python/day-09.py
10	Two Pointers	Container With Most Water	Algo/day-10.md	Notes/Two-Pointers.md	cpp/day-10.cpp	python/day-10.py
11	Sliding Window	Maximum Sum Subarray (K)	Algo/day-11.md	Notes/Sliding-Window.md	cpp/day-11.cpp	python/day-11.py
12	Sliding Window	Longest Subarray with Sum K	Algo/day-12.md	Notes/Sliding-Window.md	cpp/day-12.cpp	python/day-12.py
13	Sliding Window	Minimum Size Subarray Sum	Algo/day-13.md	Notes/Sliding-Window.md	cpp/day-13.cpp	python/day-13.py
14	Sliding Window	Subarray Product < K	Algo/day-14.md	Notes/Sliding-Window.md	cpp/day-14.cpp	python/day-14.py
15	Prefix Sum	Build Prefix Sum Array	Algo/day-15.md	Notes/Prefix-Sum.md	cpp/day-15.cpp	python/day-15.py
16	Prefix Sum	Range Sum Query	Algo/day-16.md	Notes/Prefix-Sum.md	cpp/day-16.cpp	python/day-16.py
17	Prefix Sum	Equilibrium Index	Algo/day-17.md	Notes/Prefix-Sum.md	cpp/day-17.cpp	python/day-17.py
18	DP	Kadane’s Algorithm	Algo/day-18.md	Notes/DP.md	cpp/day-18.cpp	python/day-18.py
19	DP	Circular Subarray Sum	Algo/day-19.md	Notes/DP.md	cpp/day-19.cpp	python/day-19.py
20	Arrays	Best Time to Buy & Sell Stock	Algo/day-20.md	Notes/Array.md	cpp/day-20.cpp	python/day-20.py
21	Hashing	Frequency Count	Algo/day-21.md	Notes/Hashing.md	cpp/day-21.cpp	python/day-21.py
22	Hashing	Two Sum (Unsorted)	Algo/day-22.md	Notes/Hashing.md	cpp/day-22.cpp	python/day-22.py
23	Hashing	Subarray Sum = K	Algo/day-23.md	Notes/Hashing.md	cpp/day-23.cpp	python/day-23.py
24	Hashing	Longest Consecutive Sequence	Algo/day-24.md	Notes/Hashing.md	cpp/day-24.cpp	python/day-24.py
25	Stack	Valid Parentheses	Algo/day-25.md	Notes/Stack.md	cpp/day-25.cpp	python/day-25.py
26	Stack	Next Greater Element	Algo/day-26.md	Notes/Stack.md	cpp/day-26.cpp	python/day-26.py
27	Stack	Min Stack O(1)	Algo/day-27.md	Notes/Stack.md	cpp/day-27.cpp	python/day-27.py
28	Queue	Sliding Window Maximum	Algo/day-28.md	Notes/Queue.md	cpp/day-28.cpp	python/day-28.py
29	Deque	First Negative in Window	Algo/day-29.md	Notes/Queue.md	cpp/day-29.cpp	python/day-29.py
30	Stack	Largest Histogram Area	Algo/day-30.md	Notes/Stack.md	cpp/day-30.cpp	python/day-30.py
31	Linked List	Reverse Linked List	Algo/day-31.md	Notes/LinkedList.md	cpp/day-31.cpp	python/day-31.py
32	Linked List	Detect Cycle	Algo/day-32.md	Notes/LinkedList.md	cpp/day-32.cpp	python/day-32.py
33	Linked List	Merge Two Sorted Lists	Algo/day-33.md	Notes/LinkedList.md	cpp/day-33.cpp	python/day-33.py
34	Recursion	Subsets	Algo/day-34.md	Notes/Recursion.md	cpp/day-34.cpp	python/day-34.py
35	Recursion	Permutations	Algo/day-35.md	Notes/Recursion.md	cpp/day-35.cpp	python/day-35.py
36	Trees	Tree Traversals	Algo/day-36.md	Notes/Trees.md	cpp/day-36.cpp	python/day-36.py
37	Trees	Height & Diameter	Algo/day-37.md	Notes/Trees.md	cpp/day-37.cpp	python/day-37.py
38	BST	Insert & Search	Algo/day-38.md	Notes/BST.md	cpp/day-38.cpp	python/day-38.py
39	BST	Validate BST	Algo/day-39.md	Notes/BST.md	cpp/day-39.cpp	python/day-39.py
40	Trees	Lowest Common Ancestor	Algo/day-40.md	Notes/Trees.md	cpp/day-40.cpp	python/day-40.py
41	Graph	BFS & DFS	Algo/day-41.md	Notes/Graph.md	cpp/day-41.cpp	python/day-41.py
42	Graph	Connected Components	Algo/day-42.md	Notes/Graph.md	cpp/day-42.cpp	python/day-42.py
43	Graph	Cycle Detection	Algo/day-43.md	Notes/Graph.md	cpp/day-43.cpp	python/day-43.py
44	Graph	Topological Sort	Algo/day-44.md	Notes/Graph.md	cpp/day-44.cpp	python/day-44.py
45	Graph	Shortest Path (BFS)	Algo/day-45.md	Notes/Graph.md	cpp/day-45.cpp	python/day-45.py
46	DP	Fibonacci Optimization	Algo/day-46.md	Notes/DP.md	cpp/day-46.cpp	python/day-46.py
47	DP	Climbing Stairs	Algo/day-47.md	Notes/DP.md	cpp/day-47.cpp	python/day-47.py
48	DP	Coin Change	Algo/day-48.md	Notes/DP.md	cpp/day-48.cpp	python/day-48.py
49	DP	Longest Common Subsequence	Algo/day-49.md	Notes/DP.md	cpp/day-49.cpp	python/day-49.py
50	DP	0/1 Knapsack	Algo/day-50.md	Notes/DP.md	cpp/day-50.cpp	python/day-50.py
51	Advanced C++	STL Internals	Algo/day-51.md	Notes/CPP.md	cpp/day-51.cpp	—
52	Advanced C++	Time vs Space	Algo/day-52.md	Notes/CPP.md	cpp/day-52.cpp	—
53	Advanced C++	Pointers vs References	Algo/day-53.md	Notes/CPP.md	cpp/day-53.cpp	—
54	Advanced C++	Stack vs Heap	Algo/day-54.md	Notes/CPP.md	cpp/day-54.cpp	—
55	Advanced C++	RAII & Move Semantics	Algo/day-55.md	Notes/CPP.md	cpp/day-55.cpp	—
56	Advanced Python	dict / set / Counter	Algo/day-56.md	Notes/Python.md	—	python/day-56.py
57	Advanced Python	List vs Tuple	Algo/day-57.md	Notes/Python.md	—	python/day-57.py
58	Advanced Python	OOP & Dunder	Algo/day-58.md	Notes/Python.md	—	python/day-58.py
59	Advanced Python	Iterators & Generators	Algo/day-59.md	Notes/Python.md	—	python/day-59.py
60	Advanced Python	Optimization & Profiling	Algo/day-60.md	Notes/Python.md	—	python/day-60.py

📁 Repository Structure (Recommended)

DSA/
│
├── README.md
├── Algo/
│   ├── day-01.md
│   ├── day-02.md
│   └── ...
├── Notes/
│   ├── Array.md
│   ├── Searching.md
│   ├── Two-Pointers.md
│   ├── Sliding-Window.md
│   ├── Prefix-Sum.md
│   └── DP.md
├── cpp/
│   ├── day-01.cpp
│   └── ...
└── python/
    ├── day-01.py
    └── ...

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🧠 How to Use This Repository

1. Open the Algorithm link first and understand the logic.
2. Implement the solution in C++ and Python yourself.
3. Maintain topic-wise theory and insights inside Notes/.
4. Commit daily to build strong GitHub consistency and DSA mastery.

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This repository is designed for serious developers preparing for interviews, competitive programming, and system-level thinking.